A solar panel and an inverter are two important components in a grid-tied photovoltaic power generating system. The solar panel can convert optical energy of the sun into electrical energy and output a direct current, and the inverter converts the direct current, which is output by the solar panel, into an alternating current that can be input to a power grid for use. Because solar radiation density is low, conversion efficiency of a solar battery is extremely low (approximately 10%-20%). Therefore, to improve efficiency of a grid-tied photovoltaic power generating system, conversion efficiency of an inverter needs to be improved.
In the prior art, a method for dynamically adjusting a switching on/off frequency of a power switching transistor of an inverter according to output power of the inverter is provided. When the output power is relatively small, the switching on/off frequency of the power switching transistor is changed, so that loss of the power switching transistor can be reduced in a case when the output power of the inverter is relatively small. However, if the switching on/off frequency of the power switching transistor is adjusted only according to the output power of the inverter, a relatively large error is caused, and control efficiency is low, which cannot improve conversion efficiency of the inverter effectively.